Former Manchester United goalkeeper Tim Howard has described Roy Keane as "the toughest son of a bitch I ever met".
The former USA international played with Keane between 2003 and 2005 and was at Old Trafford when Keane left the club.
Asked to choose the best player he played with, by ESPN, Howard chose Keane.
“I played with so many great players and leaders in my career, but to me, none was better than Roy Keane during my time at Manchester,” Howard said.
“He was the toughest son of a bitch I ever met. Nothing short of brilliant.
As a coach, he taught me about resilience. And never giving up on myself. I took so much of what I learned from being around him and used it over the rest of my career, trying to pass it along to the next generation.
Howard retired from football this month, at the end of Colorado Rapids' MLS campaign. He endured criticism from supporters and media during his time at Manchester United, in particular.
And he spoke about overcoming that and also Tourette's syndrome to make a fine career at the top of the game.
"From as early as I can remember, football was always the great equaliser. By now, everyone knows I have obsessive compulsive disorder and Tourette's syndrome. It hasn't been easy.
"But on the pitch, nobody cared. My facial tics, the coughing, none of it mattered as long as I stopped the ball from ending up in the back of my net.
"The field was a place where I felt free to be myself. It was a safe haven. And the greatest medicine I could have ever had.
"Football has taught me a lot about life. And who I am as a person. Out of all the games I played, I'll bet almost half ended with the media or the fans criticising me. It's only natural that self-doubt creeps in. You wonder if you can actually do this.
"If I could go back to 2003 and that nervous, naive 24-year-old kid on a plane flying to England to play for Manchester United, about to sign with the biggest football club in the world, I'd tell him to buckle up tight.
"It's going to be one hell of a ride. There will be good days and bad. You're going to go to some dark places. You're going to wonder if you should give up. People will criticise you for decades on end. But it will all be worth it.
"I'd also let the kid know the game won't always be fair. As soon as you think you've figured it out, it is going to smack you in the face and put you flat on your back.
"And in that moment, whether you're at Manchester, Everton or representing your country in the biggest sporting event on the globe, your confidence will come and go. But don't ever lose the unwavering belief that you can do this. Because you can."